I have read this thread with great interest as I have a situation with my wife's 4WD Toyota 4Runner that I was made aware of last week. The vehicle has 40K on the Michelin Cross Terrains that I was told have started a slight feathering issue. The reality of the situation I have is that the tires have been rotated and balanced every 7500 miles either at a 15K interval or at a midpoint between per the Toyota Manual in a front-to-back pattern only by the local Toyota dealers.
When they told me of the slight feathering starting to occur last week, I inquired as to why they didn't do something like a X-type rotation so that the tires ended up on the other side of the vehicle to help smooth out the feathering. Their response was essentially that it wasn't an approved rotation pattern from Toyota; therefore, they weren't allowed to do it and they did yet another front to back and vice-versa.
After reading this thread, I'm more convinced that the better thing to do now is to remove the backs and swap sides with them - essentially doing what would have been a rearward cross rotation and let it go to the next rotation. After that, I think I should do another rearward cross rotation bringing the tires from the rear to the front and crossing the current fronts to the back - that would put today's rights on the left and the lefts on the right. After that, I think it would make sense to restart the front to backs. If I did that, hopefully, it would help to smooth out the feathering and prolong the tire life.
Interested in your guys' thoughts too...